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temporarily, while too long a Forward Delay may prolong the network connection resuming.
The default value is recommended.
A suitable Hello Time ensures the switch to detect the link fault on the network but occupy
moderate network resources. The default value is recommended. If you set too long a Hello
Time, when there is packet dropped over a link, the switch may consider it as link fault and the
network device will recalculate the spanning tree accordingly.However, for too short a Hello
Time, the switch frequently sends configuration BPDU,which adds its burden and wastes the
network resources.
Too short a Max Age may cause the network device frequently calculate the spanning tree
and mistake the congestion as link fault. However, if the Max Age is too long, the network
device may not be able to discover the link fault and recalculate the spanning tree in time,
which will weaken the auto-adaptation capacity of the network. The default value is
recommended.
To avoid frequent network flapping, the values of Hello Time, Forward Delay and Maximum
Age should guarantee the following formulas equal.
2 * (forward-delay - 1seconds) >= maximum-age
maximum-age >= 2 * (hello + 1.0 seconds)
You are recommended to use the stp root primary command to specify the network diameter
and Hello Time of the switching network, thus MSTP will automatically calculate and give the
rather desirable values.
II. WEB configuration:
Click Spanning Tree, Spanning Tree Bridge Parameters, Specify Hello Time Forward Delay
Max Age, then click Apply.
